The subject matter disclosed herein relates to electric motors and other rotating equipment whose performance may be adversely affected due to entry of fluid inside the equipment and, more particularly, to a slinger shield to prevent such entry of fluid.
A slinger shield is normally a cylindrical disc with a concentric hole, which is mounted on a shaft by press fitting. To accommodate the slinger shield, an end shield is provided with a cylindrical pocket whose depth and width may be greater than or equal to the slinger shield thickness and width. Assembly of the slinger shield on the shaft thus provides a very small radial clearance between an outer diameter of the slinger shield and an inner diameter of the cylindrical pocket of the end shield. Also, there is often an axial clearance between a back face of the slinger shield and a front face of the end shield cylindrical pocket. While this clearance is required to permit relative motion between the rotating slinger shield and the stationary end shield, it is relatively small to substantially impede fluid (e.g., water) entry.
Nevertheless, fluid entry occurs and may need to be addressed for certain applications. To this end, water repellent motor seals have been proposed and generally include a sleeve that repels water by virtue of employing a surface material on which moisture resists spreading. These types of seals may be employed in high-speed universal motor applications running at, for example, over 10,000 or even over 20,000 rpm to protect the bearings from moisture damage. A fan drive with a water slinger shield has also been proposed whereby water entry is prevented by employing o-ring like seal construction. If any water that falls on the slinger during rotation is thrown off, it is directly toward a drip pan placed below. This type of seal may be applicable to a vertically mounted electric motor application. Labyrinth seals have also been used and repel water by directing it through a labyrinthine course.
Labyrinth seals can be effective in terms of achieving requirements of Ingress Protection 55 (IP55) standards but are expensive. Conversely, water repellent motor seals and slinger shields are relatively inexpensive but not as effective to provide IP-55 or higher degrees of ingress protection.